Antiviral Therapy 4: 157–161
Percentage of adherence correlates with the risk of protease inhibitor (PI) treatment failure in HIV-infected patients Jose L Casado1*, Raquel Sabido1, María J Perez-Elías1, Antonio Antela1, Jesús Oliva1, Fernando Dronda1, Blanca Mejía2 and Jesús Fortún1 1
Infectious Diseases Unit and 2Department of Pharmacy, Ramon y Cajal Hospital, Madrid, Spain
*Corresponding author: Tel/Fax: +34 91 336 8672; E-mail:
[email protected]
Objectives: To determine the effect of adherence on the rate of protease inhibitor (PI) treatment failure among human immunodeficiency virus (HIV)-infected patients. Methods: A prospective study of a cohort of 282 patients who initiated PI therapy from March 1996 to December 1997. Adherence was quantified as the percentage of prescribed doses reportedly taken and treatment failure was defined as HIV RNA levels above 200 copies/ml after 1 year on therapy. Results: Overall, 190 patients (67%) missed prescribed doses. However, mean percentage of doses taken was 91% (range, 21–100%). Demographic, virological and immunological characteristics could not predict adherence outcomes. The causes of non-adherence included intolerance or side effects (35%), complexity of treat-
ment (23%), or recurrence in active drug abuse (17%), whereas abandonment owing to HIV-related disease was uncommon (6%). A degree of adherence above 90% correlated significantly with viral suppression [relative risk (RR) 1.69; 95% confidence interval (CI) 1.1–2.56; P